Cozumel thrasher  (Toxostoma guttatum)

Classified as Critically Endangered (CR) on the IUCN Red List 2006 (1).

The Cozumel thrasher is considered to be the most threatened bird in Mexico, and was thought by some to have gone extinct until a single bird was sighted in 2004 (3). It is a medium-sized bird, similar to a mocking bird, with a distinctive long, down-curved bill. The upperparts and tail are a rich chestnut brown, with two white bars on the wings. The underparts are white, streaked with black. It has a grey face, white throat, a blackish bill and amber eyes. The male and female are similar in appearance (2).

Endemic to Cozumel Island, an island covering just 647 square kilometres, situated in the Caribbean Sea, off the Yucatán Peninsula, Mexico (2).

The Cozumel thrasher inhabits deciduous and semi-deciduous forest, and dense, scrubby and thorny woodland. It is thought to have been previously most abundant at forest edges adjacent to clearings (2) (4).

The Cozumel thrasher has often been described as a shy and secretive bird, and therefore little appears to be known about its behaviour or ecology. It is predominantly a terrestrial bird that skulks in dense vegetation, and prefers to run rather than fly when startled (4). Based on closely related species, it is presumed to be a generalised omnivore, and is believed to breed from May to July (2).

Once thought to be a common bird on Cozumel Island, the Cozumel thrasher suffered significant declines after hurricane Gilbert tore through the island in 1988, and only three individuals were found in the following seven years. After another hurricane in 1995, no thrashers were found in annual surveys until an individual was discovered in 2004 (2). The devastating effect of hurricanes remains a primary threat to any remaining, small population. However, it is believed other threats must have contributed to the decline of this species, as it is likely to have survived hurricanes for millions of years. Introduced predators, especially boas which were released onto the island in 1971, may have had a significant impact on Cozumel thrashers (4). Whilst large areas of forest remain on Cozumel Island, the ubiquitous threat of human development and associated habitat loss and degradation, is likely to increase pressures on this critically endangered species (3) (4).

Research is currently underway on the Cozumel thrasher in a project funded by the American Bird Conservancy and Conservation International (4). Surveys are urgently needed to determine whether this species still persists, and an investigation into its ecology would provide further explanation for its decline and help identify suitable conservation actions (2) (5). The Cozumel thrasher is at great risk of imminent extinction, but hopefully there is still the chance to pull it back from the brink.

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on this species see The Cozumel Thrasher website:
http://www98.homepage.villanova.edu/robert.curry/Cozumel/index.html

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org